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linux_dsm_epyc7002/arch/ia64/kernel/kprobes.c
Christoph Lameter 6065a244a0 ia64: Replace __get_cpu_var uses 
__get_cpu_var() is used for multiple purposes in the kernel source. One of
them is address calculation via the form &__get_cpu_var(x).  This calculates
the address for the instance of the percpu variable of the current processor
based on an offset.

Other use cases are for storing and retrieving data from the current
processors percpu area.  __get_cpu_var() can be used as an lvalue when
writing data or on the right side of an assignment.

__get_cpu_var() is defined as :

#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))

__get_cpu_var() always only does an address determination. However, store
and retrieve operations could use a segment prefix (or global register on
other platforms) to avoid the address calculation.

this_cpu_write() and this_cpu_read() can directly take an offset into a
percpu area and use optimized assembly code to read and write per cpu
variables.

This patch converts __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations that
use the offset.  Thereby address calculations are avoided and less registers
are used when code is generated.

At the end of the patch set all uses of __get_cpu_var have been removed so
the macro is removed too.

The patch set includes passes over all arches as well. Once these operations
are used throughout then specialized macros can be defined in non -x86
arches as well in order to optimize per cpu access by f.e.  using a global
register that may be set to the per cpu base.

Transformations done to __get_cpu_var()

1. Determine the address of the percpu instance of the current processor.

	DEFINE_PER_CPU(int, y);
	int *x = &__get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(&y);

2. Same as #1 but this time an array structure is involved.

	DEFINE_PER_CPU(int, y[20]);
	int *x = __get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(y);

3. Retrieve the content of the current processors instance of a per cpu
variable.

	DEFINE_PER_CPU(int, y);
	int x = __get_cpu_var(y)

   Converts to

	int x = __this_cpu_read(y);

4. Retrieve the content of a percpu struct

	DEFINE_PER_CPU(struct mystruct, y);
	struct mystruct x = __get_cpu_var(y);

   Converts to

	memcpy(&x, this_cpu_ptr(&y), sizeof(x));

5. Assignment to a per cpu variable

	DEFINE_PER_CPU(int, y)
	__get_cpu_var(y) = x;

   Converts to

	__this_cpu_write(y, x);

6. Increment/Decrement etc of a per cpu variable

	DEFINE_PER_CPU(int, y);
	__get_cpu_var(y)++

   Converts to

	__this_cpu_inc(y)

Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: linux-ia64@vger.kernel.org
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-08-26 13:45:52 -04:00

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/*
* Kernel Probes (KProbes)
* arch/ia64/kernel/kprobes.c
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright (C) IBM Corporation, 2002, 2004
* Copyright (C) Intel Corporation, 2005
*
* 2005-Apr Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
* <anil.s.keshavamurthy@intel.com> adapted from i386
*/
#include <linux/kprobes.h>
#include <linux/ptrace.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/preempt.h>
#include <linux/moduleloader.h>
#include <linux/kdebug.h>
#include <asm/pgtable.h>
#include <asm/sections.h>
#include <asm/uaccess.h>
extern void jprobe_inst_return(void);
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
enum instruction_type {A, I, M, F, B, L, X, u};
static enum instruction_type bundle_encoding[32][3] = {
{ M, I, I }, /* 00 */
{ M, I, I }, /* 01 */
{ M, I, I }, /* 02 */
{ M, I, I }, /* 03 */
{ M, L, X }, /* 04 */
{ M, L, X }, /* 05 */
{ u, u, u }, /* 06 */
{ u, u, u }, /* 07 */
{ M, M, I }, /* 08 */
{ M, M, I }, /* 09 */
{ M, M, I }, /* 0A */
{ M, M, I }, /* 0B */
{ M, F, I }, /* 0C */
{ M, F, I }, /* 0D */
{ M, M, F }, /* 0E */
{ M, M, F }, /* 0F */
{ M, I, B }, /* 10 */
{ M, I, B }, /* 11 */
{ M, B, B }, /* 12 */
{ M, B, B }, /* 13 */
{ u, u, u }, /* 14 */
{ u, u, u }, /* 15 */
{ B, B, B }, /* 16 */
{ B, B, B }, /* 17 */
{ M, M, B }, /* 18 */
{ M, M, B }, /* 19 */
{ u, u, u }, /* 1A */
{ u, u, u }, /* 1B */
{ M, F, B }, /* 1C */
{ M, F, B }, /* 1D */
{ u, u, u }, /* 1E */
{ u, u, u }, /* 1F */
};
/* Insert a long branch code */
static void __kprobes set_brl_inst(void *from, void *to)
{
s64 rel = ((s64) to - (s64) from) >> 4;
bundle_t *brl;
brl = (bundle_t *) ((u64) from & ~0xf);
brl->quad0.template = 0x05; /* [MLX](stop) */
brl->quad0.slot0 = NOP_M_INST; /* nop.m 0x0 */
brl->quad0.slot1_p0 = ((rel >> 20) & 0x7fffffffff) << 2;
brl->quad1.slot1_p1 = (((rel >> 20) & 0x7fffffffff) << 2) >> (64 - 46);
/* brl.cond.sptk.many.clr rel<<4 (qp=0) */
brl->quad1.slot2 = BRL_INST(rel >> 59, rel & 0xfffff);
}
/*
* In this function we check to see if the instruction
* is IP relative instruction and update the kprobe
* inst flag accordingly
*/
static void __kprobes update_kprobe_inst_flag(uint template, uint slot,
uint major_opcode,
unsigned long kprobe_inst,
struct kprobe *p)
{
p->ainsn.inst_flag = 0;
p->ainsn.target_br_reg = 0;
p->ainsn.slot = slot;
/* Check for Break instruction
* Bits 37:40 Major opcode to be zero
* Bits 27:32 X6 to be zero
* Bits 32:35 X3 to be zero
*/
if ((!major_opcode) && (!((kprobe_inst >> 27) & 0x1FF)) ) {
/* is a break instruction */
p->ainsn.inst_flag |= INST_FLAG_BREAK_INST;
return;
}
if (bundle_encoding[template][slot] == B) {
switch (major_opcode) {
case INDIRECT_CALL_OPCODE:
p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
break;
case IP_RELATIVE_PREDICT_OPCODE:
case IP_RELATIVE_BRANCH_OPCODE:
p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
break;
case IP_RELATIVE_CALL_OPCODE:
p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
break;
}
} else if (bundle_encoding[template][slot] == X) {
switch (major_opcode) {
case LONG_CALL_OPCODE:
p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
break;
}
}
return;
}
/*
* In this function we check to see if the instruction
* (qp) cmpx.crel.ctype p1,p2=r2,r3
* on which we are inserting kprobe is cmp instruction
* with ctype as unc.
*/
static uint __kprobes is_cmp_ctype_unc_inst(uint template, uint slot,
uint major_opcode,
unsigned long kprobe_inst)
{
cmp_inst_t cmp_inst;
uint ctype_unc = 0;
if (!((bundle_encoding[template][slot] == I) ||
(bundle_encoding[template][slot] == M)))
goto out;
if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
(major_opcode == 0xE)))
goto out;
cmp_inst.l = kprobe_inst;
if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.x2 == 1)) {
/* Integer compare - Register Register (A6 type)*/
if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
&&(cmp_inst.f.c == 1))
ctype_unc = 1;
} else if ((cmp_inst.f.x2 == 2)||(cmp_inst.f.x2 == 3)) {
/* Integer compare - Immediate Register (A8 type)*/
if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
ctype_unc = 1;
}
out:
return ctype_unc;
}
/*
* In this function we check to see if the instruction
* on which we are inserting kprobe is supported.
* Returns qp value if supported
* Returns -EINVAL if unsupported
*/
static int __kprobes unsupported_inst(uint template, uint slot,
uint major_opcode,
unsigned long kprobe_inst,
unsigned long addr)
{
int qp;
qp = kprobe_inst & 0x3f;
if (is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst)) {
if (slot == 1 && qp) {
printk(KERN_WARNING "Kprobes on cmp unc "
"instruction on slot 1 at <0x%lx> "
"is not supported\n", addr);
return -EINVAL;
}
qp = 0;
}
else if (bundle_encoding[template][slot] == I) {
if (major_opcode == 0) {
/*
* Check for Integer speculation instruction
* - Bit 33-35 to be equal to 0x1
*/
if (((kprobe_inst >> 33) & 0x7) == 1) {
printk(KERN_WARNING
"Kprobes on speculation inst at <0x%lx> not supported\n",
addr);
return -EINVAL;
}
/*
* IP relative mov instruction
* - Bit 27-35 to be equal to 0x30
*/
if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
printk(KERN_WARNING
"Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
addr);
return -EINVAL;
}
}
else if ((major_opcode == 5) && !(kprobe_inst & (0xFUl << 33)) &&
(kprobe_inst & (0x1UL << 12))) {
/* test bit instructions, tbit,tnat,tf
* bit 33-36 to be equal to 0
* bit 12 to be equal to 1
*/
if (slot == 1 && qp) {
printk(KERN_WARNING "Kprobes on test bit "
"instruction on slot at <0x%lx> "
"is not supported\n", addr);
return -EINVAL;
}
qp = 0;
}
}
else if (bundle_encoding[template][slot] == B) {
if (major_opcode == 7) {
/* IP-Relative Predict major code is 7 */
printk(KERN_WARNING "Kprobes on IP-Relative"
"Predict is not supported\n");
return -EINVAL;
}
else if (major_opcode == 2) {
/* Indirect Predict, major code is 2
* bit 27-32 to be equal to 10 or 11
*/
int x6=(kprobe_inst >> 27) & 0x3F;
if ((x6 == 0x10) || (x6 == 0x11)) {
printk(KERN_WARNING "Kprobes on "
"Indirect Predict is not supported\n");
return -EINVAL;
}
}
}
/* kernel does not use float instruction, here for safety kprobe
* will judge whether it is fcmp/flass/float approximation instruction
*/
else if (unlikely(bundle_encoding[template][slot] == F)) {
if ((major_opcode == 4 || major_opcode == 5) &&
(kprobe_inst & (0x1 << 12))) {
/* fcmp/fclass unc instruction */
if (slot == 1 && qp) {
printk(KERN_WARNING "Kprobes on fcmp/fclass "
"instruction on slot at <0x%lx> "
"is not supported\n", addr);
return -EINVAL;
}
qp = 0;
}
if ((major_opcode == 0 || major_opcode == 1) &&
(kprobe_inst & (0x1UL << 33))) {
/* float Approximation instruction */
if (slot == 1 && qp) {
printk(KERN_WARNING "Kprobes on float Approx "
"instr at <0x%lx> is not supported\n",
addr);
return -EINVAL;
}
qp = 0;
}
}
return qp;
}
/*
* In this function we override the bundle with
* the break instruction at the given slot.
*/
static void __kprobes prepare_break_inst(uint template, uint slot,
uint major_opcode,
unsigned long kprobe_inst,
struct kprobe *p,
int qp)
{
unsigned long break_inst = BREAK_INST;
bundle_t *bundle = &p->opcode.bundle;
/*
* Copy the original kprobe_inst qualifying predicate(qp)
* to the break instruction
*/
break_inst |= qp;
switch (slot) {
case 0:
bundle->quad0.slot0 = break_inst;
break;
case 1:
bundle->quad0.slot1_p0 = break_inst;
bundle->quad1.slot1_p1 = break_inst >> (64-46);
break;
case 2:
bundle->quad1.slot2 = break_inst;
break;
}
/*
* Update the instruction flag, so that we can
* emulate the instruction properly after we
* single step on original instruction
*/
update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
}
static void __kprobes get_kprobe_inst(bundle_t *bundle, uint slot,
unsigned long *kprobe_inst, uint *major_opcode)
{
unsigned long kprobe_inst_p0, kprobe_inst_p1;
unsigned int template;
template = bundle->quad0.template;
switch (slot) {
case 0:
*major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
*kprobe_inst = bundle->quad0.slot0;
break;
case 1:
*major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
kprobe_inst_p0 = bundle->quad0.slot1_p0;
kprobe_inst_p1 = bundle->quad1.slot1_p1;
*kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46));
break;
case 2:
*major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
*kprobe_inst = bundle->quad1.slot2;
break;
}
}
/* Returns non-zero if the addr is in the Interrupt Vector Table */
static int __kprobes in_ivt_functions(unsigned long addr)
{
return (addr >= (unsigned long)__start_ivt_text
&& addr < (unsigned long)__end_ivt_text);
}
static int __kprobes valid_kprobe_addr(int template, int slot,
unsigned long addr)
{
if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
printk(KERN_WARNING "Attempting to insert unaligned kprobe "
"at 0x%lx\n", addr);
return -EINVAL;
}
if (in_ivt_functions(addr)) {
printk(KERN_WARNING "Kprobes can't be inserted inside "
"IVT functions at 0x%lx\n", addr);
return -EINVAL;
}
return 0;
}
static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
{
unsigned int i;
i = atomic_add_return(1, &kcb->prev_kprobe_index);
kcb->prev_kprobe[i-1].kp = kprobe_running();
kcb->prev_kprobe[i-1].status = kcb->kprobe_status;
}
static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
{
unsigned int i;
i = atomic_read(&kcb->prev_kprobe_index);
__this_cpu_write(current_kprobe, kcb->prev_kprobe[i-1].kp);
kcb->kprobe_status = kcb->prev_kprobe[i-1].status;
atomic_sub(1, &kcb->prev_kprobe_index);
}
static void __kprobes set_current_kprobe(struct kprobe *p,
struct kprobe_ctlblk *kcb)
{
__this_cpu_write(current_kprobe, p);
}
static void kretprobe_trampoline(void)
{
}
/*
* At this point the target function has been tricked into
* returning into our trampoline. Lookup the associated instance
* and then:
* - call the handler function
* - cleanup by marking the instance as unused
* - long jump back to the original return address
*/
int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
{
struct kretprobe_instance *ri = NULL;
struct hlist_head *head, empty_rp;
struct hlist_node *tmp;
unsigned long flags, orig_ret_address = 0;
unsigned long trampoline_address =
((struct fnptr *)kretprobe_trampoline)->ip;
INIT_HLIST_HEAD(&empty_rp);
kretprobe_hash_lock(current, &head, &flags);
/*
* It is possible to have multiple instances associated with a given
* task either because an multiple functions in the call path
* have a return probe installed on them, and/or more than one return
* return probe was registered for a target function.
*
* We can handle this because:
* - instances are always inserted at the head of the list
* - when multiple return probes are registered for the same
* function, the first instance's ret_addr will point to the
* real return address, and all the rest will point to
* kretprobe_trampoline
*/
hlist_for_each_entry_safe(ri, tmp, head, hlist) {
if (ri->task != current)
/* another task is sharing our hash bucket */
continue;
orig_ret_address = (unsigned long)ri->ret_addr;
if (orig_ret_address != trampoline_address)
/*
* This is the real return address. Any other
* instances associated with this task are for
* other calls deeper on the call stack
*/
break;
}
regs->cr_iip = orig_ret_address;
hlist_for_each_entry_safe(ri, tmp, head, hlist) {
if (ri->task != current)
/* another task is sharing our hash bucket */
continue;
if (ri->rp && ri->rp->handler)
ri->rp->handler(ri, regs);
orig_ret_address = (unsigned long)ri->ret_addr;
recycle_rp_inst(ri, &empty_rp);
if (orig_ret_address != trampoline_address)
/*
* This is the real return address. Any other
* instances associated with this task are for
* other calls deeper on the call stack
*/
break;
}
kretprobe_assert(ri, orig_ret_address, trampoline_address);
reset_current_kprobe();
kretprobe_hash_unlock(current, &flags);
preempt_enable_no_resched();
hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
kfree(ri);
}
/*
* By returning a non-zero value, we are telling
* kprobe_handler() that we don't want the post_handler
* to run (and have re-enabled preemption)
*/
return 1;
}
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
ri->ret_addr = (kprobe_opcode_t *)regs->b0;
/* Replace the return addr with trampoline addr */
regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;
}
/* Check the instruction in the slot is break */
static int __kprobes __is_ia64_break_inst(bundle_t *bundle, uint slot)
{
unsigned int major_opcode;
unsigned int template = bundle->quad0.template;
unsigned long kprobe_inst;
/* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
if (slot == 1 && bundle_encoding[template][1] == L)
slot++;
/* Get Kprobe probe instruction at given slot*/
get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
/* For break instruction,
* Bits 37:40 Major opcode to be zero
* Bits 27:32 X6 to be zero
* Bits 32:35 X3 to be zero
*/
if (major_opcode || ((kprobe_inst >> 27) & 0x1FF)) {
/* Not a break instruction */
return 0;
}
/* Is a break instruction */
return 1;
}
/*
* In this function, we check whether the target bundle modifies IP or
* it triggers an exception. If so, it cannot be boostable.
*/
static int __kprobes can_boost(bundle_t *bundle, uint slot,
unsigned long bundle_addr)
{
unsigned int template = bundle->quad0.template;
do {
if (search_exception_tables(bundle_addr + slot) ||
__is_ia64_break_inst(bundle, slot))
return 0; /* exception may occur in this bundle*/
} while ((++slot) < 3);
template &= 0x1e;
if (template >= 0x10 /* including B unit */ ||
template == 0x04 /* including X unit */ ||
template == 0x06) /* undefined */
return 0;
return 1;
}
/* Prepare long jump bundle and disables other boosters if need */
static void __kprobes prepare_booster(struct kprobe *p)
{
unsigned long addr = (unsigned long)p->addr & ~0xFULL;
unsigned int slot = (unsigned long)p->addr & 0xf;
struct kprobe *other_kp;
if (can_boost(&p->ainsn.insn[0].bundle, slot, addr)) {
set_brl_inst(&p->ainsn.insn[1].bundle, (bundle_t *)addr + 1);
p->ainsn.inst_flag |= INST_FLAG_BOOSTABLE;
}
/* disables boosters in previous slots */
for (; addr < (unsigned long)p->addr; addr++) {
other_kp = get_kprobe((void *)addr);
if (other_kp)
other_kp->ainsn.inst_flag &= ~INST_FLAG_BOOSTABLE;
}
}
int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
unsigned long addr = (unsigned long) p->addr;
unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL);
unsigned long kprobe_inst=0;
unsigned int slot = addr & 0xf, template, major_opcode = 0;
bundle_t *bundle;
int qp;
bundle = &((kprobe_opcode_t *)kprobe_addr)->bundle;
template = bundle->quad0.template;
if(valid_kprobe_addr(template, slot, addr))
return -EINVAL;
/* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
if (slot == 1 && bundle_encoding[template][1] == L)
slot++;
/* Get kprobe_inst and major_opcode from the bundle */
get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
qp = unsupported_inst(template, slot, major_opcode, kprobe_inst, addr);
if (qp < 0)
return -EINVAL;
p->ainsn.insn = get_insn_slot();
if (!p->ainsn.insn)
return -ENOMEM;
memcpy(&p->opcode, kprobe_addr, sizeof(kprobe_opcode_t));
memcpy(p->ainsn.insn, kprobe_addr, sizeof(kprobe_opcode_t));
prepare_break_inst(template, slot, major_opcode, kprobe_inst, p, qp);
prepare_booster(p);
return 0;
}
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
unsigned long arm_addr;
bundle_t *src, *dest;
arm_addr = ((unsigned long)p->addr) & ~0xFUL;
dest = &((kprobe_opcode_t *)arm_addr)->bundle;
src = &p->opcode.bundle;
flush_icache_range((unsigned long)p->ainsn.insn,
(unsigned long)p->ainsn.insn +
sizeof(kprobe_opcode_t) * MAX_INSN_SIZE);
switch (p->ainsn.slot) {
case 0:
dest->quad0.slot0 = src->quad0.slot0;
break;
case 1:
dest->quad1.slot1_p1 = src->quad1.slot1_p1;
break;
case 2:
dest->quad1.slot2 = src->quad1.slot2;
break;
}
flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
}
void __kprobes arch_disarm_kprobe(struct kprobe *p)
{
unsigned long arm_addr;
bundle_t *src, *dest;
arm_addr = ((unsigned long)p->addr) & ~0xFUL;
dest = &((kprobe_opcode_t *)arm_addr)->bundle;
/* p->ainsn.insn contains the original unaltered kprobe_opcode_t */
src = &p->ainsn.insn->bundle;
switch (p->ainsn.slot) {
case 0:
dest->quad0.slot0 = src->quad0.slot0;
break;
case 1:
dest->quad1.slot1_p1 = src->quad1.slot1_p1;
break;
case 2:
dest->quad1.slot2 = src->quad1.slot2;
break;
}
flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
}
void __kprobes arch_remove_kprobe(struct kprobe *p)
{
if (p->ainsn.insn) {
free_insn_slot(p->ainsn.insn,
p->ainsn.inst_flag & INST_FLAG_BOOSTABLE);
p->ainsn.insn = NULL;
}
}
/*
* We are resuming execution after a single step fault, so the pt_regs
* structure reflects the register state after we executed the instruction
* located in the kprobe (p->ainsn.insn->bundle). We still need to adjust
* the ip to point back to the original stack address. To set the IP address
* to original stack address, handle the case where we need to fixup the
* relative IP address and/or fixup branch register.
*/
static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
{
unsigned long bundle_addr = (unsigned long) (&p->ainsn.insn->bundle);
unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
unsigned long template;
int slot = ((unsigned long)p->addr & 0xf);
template = p->ainsn.insn->bundle.quad0.template;
if (slot == 1 && bundle_encoding[template][1] == L)
slot = 2;
if (p->ainsn.inst_flag & ~INST_FLAG_BOOSTABLE) {
if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
/* Fix relative IP address */
regs->cr_iip = (regs->cr_iip - bundle_addr) +
resume_addr;
}
if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
/*
* Fix target branch register, software convention is
* to use either b0 or b6 or b7, so just checking
* only those registers
*/
switch (p->ainsn.target_br_reg) {
case 0:
if ((regs->b0 == bundle_addr) ||
(regs->b0 == bundle_addr + 0x10)) {
regs->b0 = (regs->b0 - bundle_addr) +
resume_addr;
}
break;
case 6:
if ((regs->b6 == bundle_addr) ||
(regs->b6 == bundle_addr + 0x10)) {
regs->b6 = (regs->b6 - bundle_addr) +
resume_addr;
}
break;
case 7:
if ((regs->b7 == bundle_addr) ||
(regs->b7 == bundle_addr + 0x10)) {
regs->b7 = (regs->b7 - bundle_addr) +
resume_addr;
}
break;
} /* end switch */
}
goto turn_ss_off;
}
if (slot == 2) {
if (regs->cr_iip == bundle_addr + 0x10) {
regs->cr_iip = resume_addr + 0x10;
}
} else {
if (regs->cr_iip == bundle_addr) {
regs->cr_iip = resume_addr;
}
}
turn_ss_off:
/* Turn off Single Step bit */
ia64_psr(regs)->ss = 0;
}
static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs)
{
unsigned long bundle_addr = (unsigned long) &p->ainsn.insn->bundle;
unsigned long slot = (unsigned long)p->addr & 0xf;
/* single step inline if break instruction */
if (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)
regs->cr_iip = (unsigned long)p->addr & ~0xFULL;
else
regs->cr_iip = bundle_addr & ~0xFULL;
if (slot > 2)
slot = 0;
ia64_psr(regs)->ri = slot;
/* turn on single stepping */
ia64_psr(regs)->ss = 1;
}
static int __kprobes is_ia64_break_inst(struct pt_regs *regs)
{
unsigned int slot = ia64_psr(regs)->ri;
unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip;
bundle_t bundle;
memcpy(&bundle, kprobe_addr, sizeof(bundle_t));
return __is_ia64_break_inst(&bundle, slot);
}
static int __kprobes pre_kprobes_handler(struct die_args *args)
{
struct kprobe *p;
int ret = 0;
struct pt_regs *regs = args->regs;
kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
struct kprobe_ctlblk *kcb;
/*
* We don't want to be preempted for the entire
* duration of kprobe processing
*/
preempt_disable();
kcb = get_kprobe_ctlblk();
/* Handle recursion cases */
if (kprobe_running()) {
p = get_kprobe(addr);
if (p) {
if ((kcb->kprobe_status == KPROBE_HIT_SS) &&
(p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {
ia64_psr(regs)->ss = 0;
goto no_kprobe;
}
/* We have reentered the pre_kprobe_handler(), since
* another probe was hit while within the handler.
* We here save the original kprobes variables and
* just single step on the instruction of the new probe
* without calling any user handlers.
*/
save_previous_kprobe(kcb);
set_current_kprobe(p, kcb);
kprobes_inc_nmissed_count(p);
prepare_ss(p, regs);
kcb->kprobe_status = KPROBE_REENTER;
return 1;
} else if (args->err == __IA64_BREAK_JPROBE) {
/*
* jprobe instrumented function just completed
*/
p = __this_cpu_read(current_kprobe);
if (p->break_handler && p->break_handler(p, regs)) {
goto ss_probe;
}
} else if (!is_ia64_break_inst(regs)) {
/* The breakpoint instruction was removed by
* another cpu right after we hit, no further
* handling of this interrupt is appropriate
*/
ret = 1;
goto no_kprobe;
} else {
/* Not our break */
goto no_kprobe;
}
}
p = get_kprobe(addr);
if (!p) {
if (!is_ia64_break_inst(regs)) {
/*
* The breakpoint instruction was removed right
* after we hit it. Another cpu has removed
* either a probepoint or a debugger breakpoint
* at this address. In either case, no further
* handling of this interrupt is appropriate.
*/
ret = 1;
}
/* Not one of our break, let kernel handle it */
goto no_kprobe;
}
set_current_kprobe(p, kcb);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
if (p->pre_handler && p->pre_handler(p, regs))
/*
* Our pre-handler is specifically requesting that we just
* do a return. This is used for both the jprobe pre-handler
* and the kretprobe trampoline
*/
return 1;
ss_probe:
#if !defined(CONFIG_PREEMPT)
if (p->ainsn.inst_flag == INST_FLAG_BOOSTABLE && !p->post_handler) {
/* Boost up -- we can execute copied instructions directly */
ia64_psr(regs)->ri = p->ainsn.slot;
regs->cr_iip = (unsigned long)&p->ainsn.insn->bundle & ~0xFULL;
/* turn single stepping off */
ia64_psr(regs)->ss = 0;
reset_current_kprobe();
preempt_enable_no_resched();
return 1;
}
#endif
prepare_ss(p, regs);
kcb->kprobe_status = KPROBE_HIT_SS;
return 1;
no_kprobe:
preempt_enable_no_resched();
return ret;
}
static int __kprobes post_kprobes_handler(struct pt_regs *regs)
{
struct kprobe *cur = kprobe_running();
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
if (!cur)
return 0;
if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
kcb->kprobe_status = KPROBE_HIT_SSDONE;
cur->post_handler(cur, regs, 0);
}
resume_execution(cur, regs);
/*Restore back the original saved kprobes variables and continue. */
if (kcb->kprobe_status == KPROBE_REENTER) {
restore_previous_kprobe(kcb);
goto out;
}
reset_current_kprobe();
out:
preempt_enable_no_resched();
return 1;
}
int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
{
struct kprobe *cur = kprobe_running();
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
switch(kcb->kprobe_status) {
case KPROBE_HIT_SS:
case KPROBE_REENTER:
/*
* We are here because the instruction being single
* stepped caused a page fault. We reset the current
* kprobe and the instruction pointer points back to
* the probe address and allow the page fault handler
* to continue as a normal page fault.
*/
regs->cr_iip = ((unsigned long)cur->addr) & ~0xFULL;
ia64_psr(regs)->ri = ((unsigned long)cur->addr) & 0xf;
if (kcb->kprobe_status == KPROBE_REENTER)
restore_previous_kprobe(kcb);
else
reset_current_kprobe();
preempt_enable_no_resched();
break;
case KPROBE_HIT_ACTIVE:
case KPROBE_HIT_SSDONE:
/*
* We increment the nmissed count for accounting,
* we can also use npre/npostfault count for accounting
* these specific fault cases.
*/
kprobes_inc_nmissed_count(cur);
/*
* We come here because instructions in the pre/post
* handler caused the page_fault, this could happen
* if handler tries to access user space by
* copy_from_user(), get_user() etc. Let the
* user-specified handler try to fix it first.
*/
if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
return 1;
/*
* In case the user-specified fault handler returned
* zero, try to fix up.
*/
if (ia64_done_with_exception(regs))
return 1;
/*
* Let ia64_do_page_fault() fix it.
*/
break;
default:
break;
}
return 0;
}
int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data)
{
struct die_args *args = (struct die_args *)data;
int ret = NOTIFY_DONE;
if (args->regs && user_mode(args->regs))
return ret;
switch(val) {
case DIE_BREAK:
/* err is break number from ia64_bad_break() */
if ((args->err >> 12) == (__IA64_BREAK_KPROBE >> 12)
|| args->err == __IA64_BREAK_JPROBE
|| args->err == 0)
if (pre_kprobes_handler(args))
ret = NOTIFY_STOP;
break;
case DIE_FAULT:
/* err is vector number from ia64_fault() */
if (args->err == 36)
if (post_kprobes_handler(args->regs))
ret = NOTIFY_STOP;
break;
default:
break;
}
return ret;
}
struct param_bsp_cfm {
unsigned long ip;
unsigned long *bsp;
unsigned long cfm;
};
static void ia64_get_bsp_cfm(struct unw_frame_info *info, void *arg)
{
unsigned long ip;
struct param_bsp_cfm *lp = arg;
do {
unw_get_ip(info, &ip);
if (ip == 0)
break;
if (ip == lp->ip) {
unw_get_bsp(info, (unsigned long*)&lp->bsp);
unw_get_cfm(info, (unsigned long*)&lp->cfm);
return;
}
} while (unw_unwind(info) >= 0);
lp->bsp = NULL;
lp->cfm = 0;
return;
}
unsigned long arch_deref_entry_point(void *entry)
{
return ((struct fnptr *)entry)->ip;
}
int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
{
struct jprobe *jp = container_of(p, struct jprobe, kp);
unsigned long addr = arch_deref_entry_point(jp->entry);
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
struct param_bsp_cfm pa;
int bytes;
/*
* Callee owns the argument space and could overwrite it, eg
* tail call optimization. So to be absolutely safe
* we save the argument space before transferring the control
* to instrumented jprobe function which runs in
* the process context
*/
pa.ip = regs->cr_iip;
unw_init_running(ia64_get_bsp_cfm, &pa);
bytes = (char *)ia64_rse_skip_regs(pa.bsp, pa.cfm & 0x3f)
- (char *)pa.bsp;
memcpy( kcb->jprobes_saved_stacked_regs,
pa.bsp,
bytes );
kcb->bsp = pa.bsp;
kcb->cfm = pa.cfm;
/* save architectural state */
kcb->jprobe_saved_regs = *regs;
/* after rfi, execute the jprobe instrumented function */
regs->cr_iip = addr & ~0xFULL;
ia64_psr(regs)->ri = addr & 0xf;
regs->r1 = ((struct fnptr *)(jp->entry))->gp;
/*
* fix the return address to our jprobe_inst_return() function
* in the jprobes.S file
*/
regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;
return 1;
}
/* ia64 does not need this */
void __kprobes jprobe_return(void)
{
}
int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
{
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
int bytes;
/* restoring architectural state */
*regs = kcb->jprobe_saved_regs;
/* restoring the original argument space */
flush_register_stack();
bytes = (char *)ia64_rse_skip_regs(kcb->bsp, kcb->cfm & 0x3f)
- (char *)kcb->bsp;
memcpy( kcb->bsp,
kcb->jprobes_saved_stacked_regs,
bytes );
invalidate_stacked_regs();
preempt_enable_no_resched();
return 1;
}
static struct kprobe trampoline_p = {
.pre_handler = trampoline_probe_handler
};
int __init arch_init_kprobes(void)
{
trampoline_p.addr =
(kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
return register_kprobe(&trampoline_p);
}
int __kprobes arch_trampoline_kprobe(struct kprobe *p)
{
if (p->addr ==
(kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip)
return 1;
return 0;
}
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